1 // Components for manipulating non-owning sequences of characters -*- C++ -*-
3 // Copyright (C) 2013-2017 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
26 * This is a Standard C++ Library header.
30 // N3762 basic_string_view library
33 #ifndef _GLIBCXX_STRING_VIEW
34 #define _GLIBCXX_STRING_VIEW 1
36 #pragma GCC system_header
38 #if __cplusplus >= 201703L
42 #include <bits/char_traits.h>
43 #include <bits/functional_hash.h>
44 #include <bits/range_access.h>
46 namespace std _GLIBCXX_VISIBILITY(default)
48 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 #define __cpp_lib_string_view 201603
53 * @class basic_string_view <string_view>
54 * @brief A non-owning reference to a string.
59 * @tparam _CharT Type of character
60 * @tparam _Traits Traits for character type, defaults to
61 * char_traits<_CharT>.
63 * A basic_string_view looks like this:
70 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
71 class basic_string_view
76 using traits_type = _Traits;
77 using value_type = _CharT;
78 using pointer = const _CharT*;
79 using const_pointer = const _CharT*;
80 using reference = const _CharT&;
81 using const_reference = const _CharT&;
82 using const_iterator = const _CharT*;
83 using iterator = const_iterator;
84 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
85 using reverse_iterator = const_reverse_iterator;
86 using size_type = size_t;
87 using difference_type = ptrdiff_t;
88 static constexpr size_type npos = size_type(-1);
90 // [string.view.cons], construct/copy
93 basic_string_view() noexcept
94 : _M_len{0}, _M_str{nullptr}
97 constexpr basic_string_view(const basic_string_view&) noexcept = default;
99 constexpr basic_string_view(const _CharT* __str)
100 : _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
104 constexpr basic_string_view(const _CharT* __str, size_type __len)
109 constexpr basic_string_view&
110 operator=(const basic_string_view&) noexcept = default;
112 // [string.view.iterators], iterators
114 constexpr const_iterator
115 begin() const noexcept
116 { return this->_M_str; }
118 constexpr const_iterator
120 { return this->_M_str + this->_M_len; }
122 constexpr const_iterator
123 cbegin() const noexcept
124 { return this->_M_str; }
126 constexpr const_iterator
127 cend() const noexcept
128 { return this->_M_str + this->_M_len; }
130 constexpr const_reverse_iterator
131 rbegin() const noexcept
132 { return const_reverse_iterator(this->end()); }
134 constexpr const_reverse_iterator
135 rend() const noexcept
136 { return const_reverse_iterator(this->begin()); }
138 constexpr const_reverse_iterator
139 crbegin() const noexcept
140 { return const_reverse_iterator(this->end()); }
142 constexpr const_reverse_iterator
143 crend() const noexcept
144 { return const_reverse_iterator(this->begin()); }
146 // [string.view.capacity], capacity
149 size() const noexcept
150 { return this->_M_len; }
153 length() const noexcept
157 max_size() const noexcept
159 return (npos - sizeof(size_type) - sizeof(void*))
160 / sizeof(value_type) / 4;
164 empty() const noexcept
165 { return this->_M_len == 0; }
167 // [string.view.access], element access
169 constexpr const _CharT&
170 operator[](size_type __pos) const noexcept
172 // TODO: Assert to restore in a way compatible with the constexpr.
173 // __glibcxx_assert(__pos < this->_M_len);
174 return *(this->_M_str + __pos);
177 constexpr const _CharT&
178 at(size_type __pos) const
180 return __pos < this->_M_len
181 ? *(this->_M_str + __pos)
182 : (__throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
183 "(which is %zu) >= this->size() "
185 __pos, this->size()),
189 constexpr const _CharT&
192 // TODO: Assert to restore in a way compatible with the constexpr.
193 // __glibcxx_assert(this->_M_len > 0);
194 return *this->_M_str;
197 constexpr const _CharT&
200 // TODO: Assert to restore in a way compatible with the constexpr.
201 // __glibcxx_assert(this->_M_len > 0);
202 return *(this->_M_str + this->_M_len - 1);
205 constexpr const _CharT*
206 data() const noexcept
207 { return this->_M_str; }
209 // [string.view.modifiers], modifiers:
212 remove_prefix(size_type __n)
214 __glibcxx_assert(this->_M_len >= __n);
220 remove_suffix(size_type __n)
221 { this->_M_len -= __n; }
224 swap(basic_string_view& __sv) noexcept
232 // [string.view.ops], string operations:
235 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
237 __glibcxx_requires_string_len(__str, __n);
238 if (__pos > this->_M_len)
239 __throw_out_of_range_fmt(__N("basic_string_view::copy: __pos "
240 "(which is %zu) > this->size() "
242 __pos, this->size());
243 size_type __rlen{std::min(__n, size_type{this->_M_len - __pos})};
244 for (auto __begin = this->_M_str + __pos,
245 __end = __begin + __rlen; __begin != __end;)
246 *__str++ = *__begin++;
251 // [string.view.ops], string operations:
253 constexpr basic_string_view
254 substr(size_type __pos, size_type __n=npos) const
256 return __pos <= this->_M_len
257 ? basic_string_view{this->_M_str + __pos,
258 std::min(__n, size_type{this->_M_len - __pos})}
259 : (__throw_out_of_range_fmt(__N("basic_string_view::substr: __pos "
260 "(which is %zu) > this->size() "
262 __pos, this->size()), basic_string_view{});
266 compare(basic_string_view __str) const noexcept
268 int __ret = traits_type::compare(this->_M_str, __str._M_str,
269 std::min(this->_M_len, __str._M_len));
271 __ret = _S_compare(this->_M_len, __str._M_len);
276 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
277 { return this->substr(__pos1, __n1).compare(__str); }
280 compare(size_type __pos1, size_type __n1,
281 basic_string_view __str, size_type __pos2, size_type __n2) const
282 { return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2)); }
285 compare(const _CharT* __str) const noexcept
286 { return this->compare(basic_string_view{__str}); }
289 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
290 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
293 compare(size_type __pos1, size_type __n1,
294 const _CharT* __str, size_type __n2) const
296 return this->substr(__pos1, __n1)
297 .compare(basic_string_view(__str, __n2));
301 find(basic_string_view __str, size_type __pos = 0) const noexcept
302 { return this->find(__str._M_str, __pos, __str._M_len); }
305 find(_CharT __c, size_type __pos=0) const noexcept;
308 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
311 find(const _CharT* __str, size_type __pos=0) const noexcept
312 { return this->find(__str, __pos, traits_type::length(__str)); }
315 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
316 { return this->rfind(__str._M_str, __pos, __str._M_len); }
319 rfind(_CharT __c, size_type __pos = npos) const noexcept;
322 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
325 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
326 { return this->rfind(__str, __pos, traits_type::length(__str)); }
329 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
330 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
333 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
334 { return this->find(__c, __pos); }
337 find_first_of(const _CharT* __str, size_type __pos, size_type __n) const;
340 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
341 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
344 find_last_of(basic_string_view __str,
345 size_type __pos = npos) const noexcept
346 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
349 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
350 { return this->rfind(__c, __pos); }
353 find_last_of(const _CharT* __str, size_type __pos, size_type __n) const;
356 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
357 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
360 find_first_not_of(basic_string_view __str,
361 size_type __pos = 0) const noexcept
362 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
365 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
368 find_first_not_of(const _CharT* __str,
369 size_type __pos, size_type __n) const;
372 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
374 return this->find_first_not_of(__str, __pos,
375 traits_type::length(__str));
379 find_last_not_of(basic_string_view __str,
380 size_type __pos = npos) const noexcept
381 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
384 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
387 find_last_not_of(const _CharT* __str,
388 size_type __pos, size_type __n) const;
391 find_last_not_of(const _CharT* __str,
392 size_type __pos = npos) const noexcept
394 return this->find_last_not_of(__str, __pos,
395 traits_type::length(__str));
399 _M_check(size_type __pos, const char* __s) const
401 if (__pos > this->size())
402 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
403 "this->size() (which is %zu)"),
404 __s, __pos, this->size());
408 // NB: _M_limit doesn't check for a bad __pos value.
410 _M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
412 const bool __testoff = __off < this->size() - __pos;
413 return __testoff ? __off : this->size() - __pos;
419 _S_compare(size_type __n1, size_type __n2) noexcept
421 return difference_type{__n1 - __n2} > std::numeric_limits<int>::max()
422 ? std::numeric_limits<int>::max()
423 : difference_type{__n1 - __n2} < std::numeric_limits<int>::min()
424 ? std::numeric_limits<int>::min()
425 : static_cast<int>(difference_type{__n1 - __n2});
429 const _CharT* _M_str;
432 // [string.view.comparison], non-member basic_string_view comparison function
436 // Identity transform to create a non-deduced context, so that only one
437 // argument participates in template argument deduction and the other
438 // argument gets implicitly converted to the deduced type. See n3766.html.
439 template<typename _Tp>
440 using __idt = common_type_t<_Tp>;
443 template<typename _CharT, typename _Traits>
445 operator==(basic_string_view<_CharT, _Traits> __x,
446 basic_string_view<_CharT, _Traits> __y) noexcept
447 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
449 template<typename _CharT, typename _Traits>
451 operator==(basic_string_view<_CharT, _Traits> __x,
452 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
453 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
455 template<typename _CharT, typename _Traits>
457 operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
458 basic_string_view<_CharT, _Traits> __y) noexcept
459 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
461 template<typename _CharT, typename _Traits>
463 operator!=(basic_string_view<_CharT, _Traits> __x,
464 basic_string_view<_CharT, _Traits> __y) noexcept
465 { return !(__x == __y); }
467 template<typename _CharT, typename _Traits>
469 operator!=(basic_string_view<_CharT, _Traits> __x,
470 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
471 { return !(__x == __y); }
473 template<typename _CharT, typename _Traits>
475 operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
476 basic_string_view<_CharT, _Traits> __y) noexcept
477 { return !(__x == __y); }
479 template<typename _CharT, typename _Traits>
481 operator< (basic_string_view<_CharT, _Traits> __x,
482 basic_string_view<_CharT, _Traits> __y) noexcept
483 { return __x.compare(__y) < 0; }
485 template<typename _CharT, typename _Traits>
487 operator< (basic_string_view<_CharT, _Traits> __x,
488 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
489 { return __x.compare(__y) < 0; }
491 template<typename _CharT, typename _Traits>
493 operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
494 basic_string_view<_CharT, _Traits> __y) noexcept
495 { return __x.compare(__y) < 0; }
497 template<typename _CharT, typename _Traits>
499 operator> (basic_string_view<_CharT, _Traits> __x,
500 basic_string_view<_CharT, _Traits> __y) noexcept
501 { return __x.compare(__y) > 0; }
503 template<typename _CharT, typename _Traits>
505 operator> (basic_string_view<_CharT, _Traits> __x,
506 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
507 { return __x.compare(__y) > 0; }
509 template<typename _CharT, typename _Traits>
511 operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
512 basic_string_view<_CharT, _Traits> __y) noexcept
513 { return __x.compare(__y) > 0; }
515 template<typename _CharT, typename _Traits>
517 operator<=(basic_string_view<_CharT, _Traits> __x,
518 basic_string_view<_CharT, _Traits> __y) noexcept
519 { return __x.compare(__y) <= 0; }
521 template<typename _CharT, typename _Traits>
523 operator<=(basic_string_view<_CharT, _Traits> __x,
524 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
525 { return __x.compare(__y) <= 0; }
527 template<typename _CharT, typename _Traits>
529 operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
530 basic_string_view<_CharT, _Traits> __y) noexcept
531 { return __x.compare(__y) <= 0; }
533 template<typename _CharT, typename _Traits>
535 operator>=(basic_string_view<_CharT, _Traits> __x,
536 basic_string_view<_CharT, _Traits> __y) noexcept
537 { return __x.compare(__y) >= 0; }
539 template<typename _CharT, typename _Traits>
541 operator>=(basic_string_view<_CharT, _Traits> __x,
542 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
543 { return __x.compare(__y) >= 0; }
545 template<typename _CharT, typename _Traits>
547 operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
548 basic_string_view<_CharT, _Traits> __y) noexcept
549 { return __x.compare(__y) >= 0; }
551 // [string.view.io], Inserters and extractors
552 template<typename _CharT, typename _Traits>
553 inline basic_ostream<_CharT, _Traits>&
554 operator<<(basic_ostream<_CharT, _Traits>& __os,
555 basic_string_view<_CharT,_Traits> __str)
556 { return __ostream_insert(__os, __str.data(), __str.size()); }
559 // basic_string_view typedef names
561 using string_view = basic_string_view<char>;
562 #ifdef _GLIBCXX_USE_WCHAR_T
563 using wstring_view = basic_string_view<wchar_t>;
565 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
566 using u16string_view = basic_string_view<char16_t>;
567 using u32string_view = basic_string_view<char32_t>;
570 // [string.view.hash], hash support:
572 template<typename _Tp>
576 struct hash<string_view>
577 : public __hash_base<size_t, string_view>
580 operator()(const string_view& __str) const noexcept
581 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
585 struct __is_fast_hash<hash<string_view>> : std::false_type
588 #ifdef _GLIBCXX_USE_WCHAR_T
590 struct hash<wstring_view>
591 : public __hash_base<size_t, wstring>
594 operator()(const wstring_view& __s) const noexcept
595 { return std::_Hash_impl::hash(__s.data(),
596 __s.length() * sizeof(wchar_t)); }
600 struct __is_fast_hash<hash<wstring_view>> : std::false_type
604 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
606 struct hash<u16string_view>
607 : public __hash_base<size_t, u16string_view>
610 operator()(const u16string_view& __s) const noexcept
611 { return std::_Hash_impl::hash(__s.data(),
612 __s.length() * sizeof(char16_t)); }
616 struct __is_fast_hash<hash<u16string_view>> : std::false_type
620 struct hash<u32string_view>
621 : public __hash_base<size_t, u32string_view>
624 operator()(const u32string_view& __s) const noexcept
625 { return std::_Hash_impl::hash(__s.data(),
626 __s.length() * sizeof(char32_t)); }
630 struct __is_fast_hash<hash<u32string_view>> : std::false_type
634 inline namespace literals
636 inline namespace string_view_literals
638 inline constexpr basic_string_view<char>
639 operator""sv(const char* __str, size_t __len)
640 { return basic_string_view<char>{__str, __len}; }
642 #ifdef _GLIBCXX_USE_WCHAR_T
643 inline constexpr basic_string_view<wchar_t>
644 operator""sv(const wchar_t* __str, size_t __len)
645 { return basic_string_view<wchar_t>{__str, __len}; }
648 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
649 inline constexpr basic_string_view<char16_t>
650 operator""sv(const char16_t* __str, size_t __len)
651 { return basic_string_view<char16_t>{__str, __len}; }
653 inline constexpr basic_string_view<char32_t>
654 operator""sv(const char32_t* __str, size_t __len)
655 { return basic_string_view<char32_t>{__str, __len}; }
657 } // namespace string_literals
658 } // namespace literals
660 _GLIBCXX_END_NAMESPACE_VERSION
663 #include <bits/string_view.tcc>
665 #endif // __cplusplus <= 201402L
667 #endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW